1. Field of the Invention
The present invention relates to an image input/output device in which an image information detection section for receiving reflected light from an image information object to detect the image information of the object, and a self-luminous image display section for displaying an image based on the image information detected by the image information detection section are attached together in a back-to-back arrangement, and an image information reading method therefor.
2. Description of the Prior Art
Image input/output devices in which a flat image sensor and a flat display are attached together in a back-to-back arrangement have been developed in the art.
For example, JP 5-100645A discloses a device for reading/processing/displaying external information. The device includes a display device such as a flat panel display and a scanner for reading external information integrally attached to the back side of the display device, with the backlight (light source) of the display device being used also as the light source of the scanner. An information processing device is integrated with the scanner and the display device so that scanned information from the scanner is displayed on the display device. It is stated that since the scanner is provided so as to form a part of the whole device, it is possible to display information from the scanner with a small and light-weight device.
JP 6-175590A discloses a card-shaped display device including a two-dimensional contact image sensor to be placed closely on a scanned object for reading the image of the object in the image-reading area, a liquid crystal display provided above the two-dimensional image sensor, and a double-sided light source provided between the two-dimensional image sensor and the liquid crystal display for illuminating the surface of the scanned object through the two-dimensional image sensor and also for displaying the image of the object on the liquid crystal display. It is stated that using the card-shaped device in which an image-reading section and a display section are integrated together, it is possible to read the image of the scanned object with the two-dimensional image sensor placed closely on the scanned object and to immediately display the obtained image on the liquid crystal display.
JP 7-322012A discloses an image input/output device including a two-dimensional contact image sensor and a liquid crystal display for displaying, on an enlarged scale, whole or part of image information obtained by the image sensor. The image sensor and the liquid crystal display are arranged so that the image-reading surface of the image sensor and the display surface of the liquid crystal display are the front and back surfaces, respectively, of the image input/output device, with the display surface being located directly above the image-reading area. The publication states as follows. Since the display surface is located directly above the image-reading area, the place where an image is being obtained corresponds to the place where it is being displayed, thereby eliminating the possibility of mis-reading as the user can obtain the image while viewing it on the display. Moreover, the device can be provided with an image enlarging function and a translation function, thus realizing a compact and easy-to-use image input/output device. Furthermore, in the image input/output device disclosed in JP 7-322012A, a flat light source (including a light source, a reflective member and a light guide plate) is provided between the front-side liquid crystal display and the back-side image sensor, and the flat light source is used as the backlight for the liquid crystal display and as the light source for the image sensor (a light source for illuminating the scanned object).
When such an image input/output device is used as a portable information-collecting tool, it is necessary to reduce the thickness of the device as much as possible in order to improve the portability thereof.
However, as illustrated in FIG. 9, it is difficult to reduce the thickness of a conventional image input/output device 300 because of the structure thereof in which three components, i.e., a display 310, a light source 320 and an image sensor (scanner) 330, are layered on one another.